One of our older blog posts on 5 Factors that will Shorten the Life of Your UPS Battery got me thinking about this topic. While each of those factors is important, I thought it would be useful to discuss a few of the variables users have some control over (dictating when power goes out can be tough after all).

Generally, despite some growing lithium popularity (here's a quick Lithium Iron Phosphate vs. Lead-Acid Batteries for UPSes breakdown for anyone interested), the internal batteries in most single phase, and even many 3 phase UPSes, are Sealed Lead Acid (SLA) batteries (a.k.a. Valve-Regulated Sealed Lead Acid or VRLA). More specifically, they are usually Absorbed Glass Mat Sealed Lead Acid Batteries (AGM SLA).

The specifics of a given battery may vary a bit, so I'll give the standard "defer to the manufacturer's documentation & specification for specifics" disclaimer. Generally speaking, the items & suggestions I'll outline here should apply to most AGM SLAs used in UPSes today.

With that in mind, here are some of the tips I have on improving UPS battery life:

Operate your UPS at or near room temperature. For every 15 °F above 77 °F (ambient temperature) you can cut expected battery life in half. As a reference, UPS batteries are generally specified to last 3-5 (or 4-6 depending on who you ask) years under normal operating conditions. If the room is 92 °F, you can drop that to 1.5-2.5 years (or 2-3). Spot cooling can be helpful in environments where room temperature is too high.

Avoid prolonged storage. When stored, UPS batteries self-dissipate at a rate of about 2-3% per month. If you've ever waited a few years to unbox a "battery dependent" UPS & it would not power on, discharged batteries may be to blame.

If you have to store batteries for more than 3-6 months, have a plan to charge them regularly. Recharge times will vary depending on the UPS, but a 24 hour recharge should be more than enough in most cases. Some may only take a few hours. In most cases you can probably get away with longer storage periods without a recharge, but I'd rather be conservative with this estimate.

Do NOT store batteries in a discharged state. If you have to store UPS batteries for an extended period, don't store them in a discharged state. For example, if a UPS ran on battery and powered off, recharging it before putting it into storage is a good idea. The self-dissipation that occurs will only be worse starting from a discharged state, and the batteries could reach an "unrecoverable" state sooner.

Interested in other inputs, tips, and questions from other community members (or vendors).

Anyone have any other battery life tips? Or stories of dead batteries that could have been avoided?

You're correct that "standard" lead-acid batteries (whether liquid acid or gelled electrolyte) are not meant for long-cycle and deep discharge. Although some marketing guy runs the discharge curve out to 2098, adding batteries is really a solution for capacity, not run-time.

The phone company (traditionally) was the model for battery operation. Using open-frame 48V acid batteries, the phone company provided its own power, independent of the grid. (Well, there really wasn't a grid then, either.) It's a solution that's worked for centuries.

You can purchase items that area called "DC generators." What they really are is the DC-to-AC part of a UPS. You provide the DC batteries and it provides the part that converts it to AC. (It's typically just a DC-powered multi-vibrator connected to a step-up transformer and filtering mechanism.)

[In the WWII days, these were actually mechanical vibrators (picture a relay clicking on and off repeatedly at 60 or 400 cycles per second.) The "chopped" DC was a sort of AC and could then be sent to transformers to change to the 200+ volts needed for tube equipment like radios.]

We have some remote radio sites that use these DC generators. We provide the banks of deep-discharge (marine) batteries and the chargers.

Put together an AC-to-DC convert, a battery, and a DC-to-AC inverter and you have a full-time real sinewave UPS. You can buy these from UPS companies if you want small ones. For large ones, you design your own and buy the components.

You won't find a lot of SMB guys familiar with this type of setup. That doesn't mean they're not in use nearly everywhere that power is important.

I checked with tech support and there is a power saver mode on the EX. I think when you are below 5% load (I can't remember) the UPS will shutoff after 5 minutes when on battery. The goal to prevent the batteries from being discharged too slowly after the main equipment has shutdown.

Obviously this isn't what you want for your application, so you can eliminate this through our UPS config tool.

I would only buy standby batt for UPS only after 24-36 months and change them out almost immediately (unless the UPS is already screaming to replace batt)

Taking a "just-in-time" approach to buying replacement batteries is definitely a good idea. I think most private sector companies and home consumers can do this fairly easily. Sometimes in the public sector (e.g. schools) we see instances where the time of purchase is decoupled from the time the batteries can be installed due to fund availability and budgeting.

I would only buy standby batt for UPS only after 24-36 months and change them out almost immediately (unless the UPS is already screaming to replace batt)

Taking a "just-in-time" approach to buying replacement batteries is definitely a good idea. I think most private sector companies and home consumers can do this fairly easily. Sometimes in the public sector (e.g. schools) we see instances where the time of purchase is decoupled from the time the batteries can be installed due to fund availability and budgeting.

Then thats not the right approach or that you have met a very bad UPS sales-person.

UPS Batt can last 3-5 years or sometimes longer (I have seen like 7 yrs) before UPS screams to replace batt. However, unused batt only have a shelf-life of approx 24-36 months (not taking when it was manufacture and sitting in warehouse etc).....there are many conditions that can slowly discharge batt like placing it on floor, wet or moist air or even if the room is too hot or cold.

I would only buy standby batt for UPS only after 24-36 months and change them out almost immediately (unless the UPS is already screaming to replace batt)

Taking a "just-in-time" approach to buying replacement batteries is definitely a good idea. I think most private sector companies and home consumers can do this fairly easily. Sometimes in the public sector (e.g. schools) we see instances where the time of purchase is decoupled from the time the batteries can be installed due to fund availability and budgeting.

Then thats not the right approach or that you have met a very bad UPS sales-person.

UPS Batt can last 3-5 years or sometimes longer (I have seen like 7 yrs) before UPS screams to replace batt. However, unused batt only have a shelf-life of approx 24-36 months (not taking when it was manufacture and sitting in warehouse etc).....there are many conditions that can slowly discharge batt like placing it on floor, wet or moist air or even if the room is too hot or cold.

Thanks for the reply adrian_ych Which approach are you referring to? The "just-in-time" comment? What I mean by that is "buy them as close to when you will need them as practical".

I would only buy standby batt for UPS only after 24-36 months and change them out almost immediately (unless the UPS is already screaming to replace batt)

Taking a "just-in-time" approach to buying replacement batteries is definitely a good idea. I think most private sector companies and home consumers can do this fairly easily. Sometimes in the public sector (e.g. schools) we see instances where the time of purchase is decoupled from the time the batteries can be installed due to fund availability and budgeting.

Then thats not the right approach or that you have met a very bad UPS sales-person.

UPS Batt can last 3-5 years or sometimes longer (I have seen like 7 yrs) before UPS screams to replace batt. However, unused batt only have a shelf-life of approx 24-36 months (not taking when it was manufacture and sitting in warehouse etc).....there are many conditions that can slowly discharge batt like placing it on floor, wet or moist air or even if the room is too hot or cold.

Thanks for the reply adrian_ych Which approach are you referring to? The "just-in-time" comment? What I mean by that is "buy them as close to when you will need them as practical".

The approach where people buy spare batteries with new UPS "due to budget constraints".

I would only buy standby batt for UPS only after 24-36 months and change them out almost immediately (unless the UPS is already screaming to replace batt)

Taking a "just-in-time" approach to buying replacement batteries is definitely a good idea. I think most private sector companies and home consumers can do this fairly easily. Sometimes in the public sector (e.g. schools) we see instances where the time of purchase is decoupled from the time the batteries can be installed due to fund availability and budgeting.

Then thats not the right approach or that you have met a very bad UPS sales-person.

UPS Batt can last 3-5 years or sometimes longer (I have seen like 7 yrs) before UPS screams to replace batt. However, unused batt only have a shelf-life of approx 24-36 months (not taking when it was manufacture and sitting in warehouse etc).....there are many conditions that can slowly discharge batt like placing it on floor, wet or moist air or even if the room is too hot or cold.

Thanks for the reply adrian_ych Which approach are you referring to? The "just-in-time" comment? What I mean by that is "buy them as close to when you will need them as practical".

The approach where people buy spare batteries with new UPS "due to budget constraints".

Ah. I was not suggesting buying new replacement batteries with new UPSes.

What I meant was: use-it-or-lose-it style budgets can lead to organizations having funding at times that don't perfectly align with when they will be able to install new UPSes or replacement batteries for older UPSes

For example, say an organization has to spend funds by July 1st but won't be in a position to replace batteries in old UPSes or install the new UPSes (that would have internal batteries) until the next year. In that scenario, you may see the UPSes or replacement batteries sit on a shelf for a while.

For example, say an organization has to spend funds by July 1st but won't be in a position to replace batteries in old UPSes or install the new UPSes (that would have internal batteries) until the next year. In that scenario, you may see the UPSes or replacement batteries sit on a shelf for a while.

But how would they know when to change ? If the UPS is not asking to change batt, why buy them ?

In those "budget" restraints, I would not get the batt at all...else if I get the batt, I would change them out.

Then there is this consideration if the UPS is old....like 5yrs old.....change batt or change UPS (then wait another 36 mths to see if UPS fails) ?

But how would they know when to change ? If the UPS is not asking to change batt, why buy them ?

In those "budget" restraints, I would not get the batt at all...else if I get the batt, I would change them out.

Good questions. Those situations would generally come up at scale, multiple sites, many UPSes. e.g. For 100 UPSes across 10 sites, is it more efficient to wait for each UPS to indicate it has bad batteries (or raise a similar replace battery warning) and deploy someone to replace then as it comes up one by one, or plan for replacement ahead of time once batteries are X years old and have a project to replace them all?

To the "If the UPS is not asking to change batt, why buy them ?" question, the main reason to change the batteries if the UPS does not indicate it is needed would be proactive preventative maintenance. For example, if a fleet of UPSes have batteries that have been in service for over five years but aren't yet failing self-tests, it can still be prudent to replace batteries given that we know what expected useful life is for these type of AGM SLA batteries.

In either case, it is a good idea to avoid storing batteries for
extended periods (i.e. wait until around the time the batteries are needed to source them). In the (hopefully rare) scenarios where batteries or
UPSes with internal batteries do end up being stored for extended
periods, they should be charged from time to time.

adrian_ych wrote:

Then there is this consideration if the UPS is old....like 5yrs old.....change batt or change UPS (then wait another 36 mths to see if UPS fails) ?

Replace UPS vs only replace battery is another consideration and an interesting topic to discuss. A few things would drive that decision would be cost, type of UPS, operating conditions, warranties, etc.

Regarding battery life we take a more pro-active stance on replacing batteries; Batteries are replaced on a 4 year cycle based on UL regulations regarding UPSs, or when the UPS indicates an issue with the battery (whichever happens first). Don't wait for your UPS to indicate failure, as most will only figure out that failure when they use the batteries. Also, do your best to not store batteries for more than a couple months. The previously mentioned 4 year life cycle is based on manufacture date of the battery and the less time that battery is in your UPS the less cost effective it is.

Regarding battery life we take a more pro-active stance on replacing batteries; Batteries are replaced on a 4 year cycle based on UL regulations regarding UPSs, or when the UPS indicates an issue with the battery (whichever happens first). Don't wait for your UPS to indicate failure, as most will only figure out that failure when they use the batteries. Also, do your best to not store batteries for more than a couple months. The previously mentioned 4 year life cycle is based on manufacture date of the battery and the less time that battery is in your UPS the less cost effective it is.

I'm a proponent of planning for replacement proactively too. Generally, we find somewhere in that 3-5 year range works for most. Not waiting for an alarm locally on the UPS is another good general tip.

Regarding battery life we take a more pro-active stance on replacing batteries; Batteries are replaced on a 4 year cycle based on UL regulations regarding UPSs, or when the UPS indicates an issue with the battery (whichever happens first). Don't wait for your UPS to indicate failure, as most will only figure out that failure when they use the batteries. Also, do your best to not store batteries for more than a couple months. The previously mentioned 4 year life cycle is based on manufacture date of the battery and the less time that battery is in your UPS the less cost effective it is.

I'm a proponent of planning for replacement proactively too. Generally, we find somewhere in that 3-5 year range works for most. Not waiting for an alarm locally on the UPS is another good general tip.

What capacity UPSes do you have?

Do you have a means of determining battery manufacture date?

We have mostly 2000 VA UPSs from differing manufacturers

Everyone has a means of determining battery manufacture date just by looking at the battery.

Regarding battery life we take a more pro-active stance on replacing batteries; Batteries are replaced on a 4 year cycle based on UL regulations regarding UPSs, or when the UPS indicates an issue with the battery (whichever happens first). Don't wait for your UPS to indicate failure, as most will only figure out that failure when they use the batteries. Also, do your best to not store batteries for more than a couple months. The previously mentioned 4 year life cycle is based on manufacture date of the battery and the less time that battery is in your UPS the less cost effective it is.

I'm a proponent of planning for replacement proactively too. Generally, we find somewhere in that 3-5 year range works for most. Not waiting for an alarm locally on the UPS is another good general tip.

What capacity UPSes do you have?

Do you have a means of determining battery manufacture date?

We have mostly 2000 VA UPSs from differing manufacturers

Everyone has a means of determining battery manufacture date just by looking at the battery.